I highly doubt that Brexit will set the EU back ten years compared to the rest of the world. The EU has always been intensely bureaucratic, and negotiations about trade and immigration are pretty routine. Even if the vote had gone the other way, I expect that the UK would have wanted to renegotiate some of its agreements with the EU. While EU bureaucracy is likely to be focused on signing new agreements with the UK for the next little while, I doubt that the EU will actually become significantly more bureaucratic as a result. It may even become less bureaucratic in the long run if members see Brexit as a sign that the EU needs to be more agile. HOWEVER a whole bunch of people who firmly believe they have better shit to do are now going to have to burn a shit ton of blood and treasure on treaties and trade agreements and boring shit like that while the rest of the world aren't.